Successful advancements in molecular diagnostics related to a wide range of fields, including medical, biological, environmental, forensics, and food safety, drives the need for preservation of nucleic acid integrity during sample collection, transportation, processing, and storage.1 RNA tends to be more labile than DNA and can be hydrolyzed readily when exposed to conditions of high pH, metal cations, or high temperatures, as well as contaminating RNA ribonucleases (RNases). RNases are known to be present endogenously in cells, tissues, body oils, and bacteria and/or fungi in airborne dust particles, the main concern for preserving the integrity of RNA.2 There are a number of commercial products for preservation during sample collection: RNAlater Tissue Collection: RNA Stabilization Solution (Life Technologies, Carlsbad, Calif.), RNAlater RNA Stabilization Reagent (Qiagen, Valencia, Ca), PAXgene tubes (PreAnalytix, Valencia, Calif.), and RNAstable (Biomatrica, San Diego, Calif.). Alternatively, RNA can be protected within a physical barrier employing materials similar to those used in DNA encapsulation: liposomes, micelles, or polymers.3-6 
The most common method for maintaining nucleic acid integrity, in general, is freezing at low temperature (−20° C. or −80° C.).9 This approach is not practical for routine specimen processing, storage, or shipping when under austere field conditions. Furthermore, the costs associated with maintaining large sets of samples under the necessary conditions over long periods of time can be prohibitive.10-12 
To address these issues, several technologies have been developed for the stabilization and storage of nucleic acids at room temperature. These technologies are primarily based on three principles.
The first is anhydrobiosis, the dehydration process used by some organisms to survive extreme conditions.13,14 These methods include spray drying, spray-freeze-drying, air drying, and lyophilization with or without additives (i.e. trehalose) commonly used for DNA preservation.15-19 One study also indicated that anhydrobiosis worked well for RNA preservation.20 While in the dry state, the matrix components form a thermo-stable barrier around the DNA protecting the sample from damage and degradation. The DNA can be recovered by rehydration as the matrix will completely dissolve.11,21,22 
The second approach to stabilization is to use chemicals or proteins to bind nucleic acids, changing their characteristics and interactions to provide stability. Several chemicals and compounds have been reported to preserve nucleic acids at room temperature from periods of weeks to months. DNA-binding protein from starved cells (Dps) and poly(A) binding protein (Pab1p) were reported to stabilize DNA and mRNA, respectively.12,23-38 Commercial products, such as RNAlater and Trizol (Life Technologies), are based on this approach and have been documented to stabilize nucleic acids at room temperature for long periods of time.11,27,30,39-41 
Physically protecting nucleic acids from the environment, through encapsulation or adsorption onto a solid support, is the third of the stabilization principles and has emerged for the delivery of gene therapeutics. A range of materials, including liposomes, metal particles, polymers, potato starch, silk fibron and surfactants, have been developed with these applications in mind.3,42-48 
Field collection of samples for molecular analysis presents distinct challenges owing to the lack of laboratory facilities and renders the preservation of nucleic acids necessary for storage and transportation. It is also critical that these approaches provide methods for recovery of the nucleic acids without contaminating downstream molecular diagnostic assays.